Anti-basement membrane antibody responses cause a portion of glomerulonephritis, tubulointerstitial nephritis and pulmonary hemorrhage or hemosiderosis in man. Virtually nothing is known about the basement membrane antigens or the events leading to their immunogenicity. The studies outlined in this proposal employ radioimmunoassay and immunoabsorptive techniques to identify, quantitate, monitor, manipulate and isolate the antigens responsible for similar pathogenic immune responses in experimental animals. Better understanding of the normal and abnormal metabolism of these materials should increase our understanding of the events responsible for the spontaneous induction of anti-basement membrane antibody responses. In recent years, work in our laboratory and others have shown that nonbasement membrane antigens, either anatomically present in or trapper or "planted" in the glomerulus, can be involved in nephritogenic immune responses. Studies are outlined to identify the nature and ultimately the metabolism of the nephritogenic nonbasement membrane glomerualar antigens normally found within the glomerulus. Techniques similar to those described for the study of the basement membrane antigens will be employed. The possibility that materials from organisms pathogenic to man become trapped or "planted" in the glomeruli for subsequent nephritogenic in situ immune complex formation will be evaluated.